RESUMO
A considerable proportion of stroke survivors are prescribed with proton pump inhibitors (PPIs). Our study indicated that PPI use is associated with an increased risk of osteoporosis, hip fracture, and vertebral fracture in stroke patients. The risk tends to increase as the cumulative doses of PPIs increase. INTRODUCTION: A considerable proportion of stroke survivors are prescribed with proton pump inhibitors (PPIs). Our study investigated the association between PPI use and the risk of osteoporosis and fracture among stroke survivors. METHODS: A population-based propensity-matched retrospective cohort study was conducted using the National Health Insurance Research Database in Taiwan. Patients diagnosed with a new stroke between 2000 and 2012 were identified. After propensity score matching, 10,596 patients were enrolled, and 5298 patients were each assigned to the PPI user and non-user groups. Hazard ratios (HRs) were calculated for the risk of osteoporosis, hip fracture, and vertebral fractures according to PPI use or non-use. Sensitivity analyses were conducted to evaluate the dose effects of PPI. RESULTS: PPI use after stroke was associated with an increased risk of osteoporosis, hip fracture, or vertebral fracture, with an adjusted HR (aHR) of 1.28 (P < 0.001). The aHRs were also significant for each outcome: osteoporosis, 1.26 (P < 0.001); hip fracture, 1.18 (P = 0.048); vertebral fracture, 1.33 (P < 0.001). A pattern of dose effect was identified. For any event (osteoporosis/hip fracture/vertebral fracture), the aHR for PPI use of 1-90, 91-365, and > 365 cDDDs was 1.22 (P < 0.001), 1.27 (P < 0.001), and 1.66 (P < 0.001), respectively. For each outcome, the highest dose was associated with the highest risk, with aHR of 1.79 (P < 0.001), 1.41 (P = 0.039), and 1.82 (P < 0.001) for osteoporosis, hip fracture, and vertebral fracture, respectively. Age- and sex-stratified analyses revealed similar patterns. CONCLUSIONS: PPI use is associated with an increased risk of osteoporosis, hip fracture, and vertebral fracture in stroke patients.
Assuntos
Osteoporose/induzido quimicamente , Fraturas por Osteoporose/induzido quimicamente , Inibidores da Bomba de Prótons/efeitos adversos , Acidente Vascular Cerebral/complicações , Adulto , Idoso , Estudos de Coortes , Relação Dose-Resposta a Droga , Feminino , Fraturas do Quadril/induzido quimicamente , Fraturas do Quadril/epidemiologia , Humanos , Incidência , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Osteoporose/epidemiologia , Fraturas por Osteoporose/epidemiologia , Inibidores da Bomba de Prótons/administração & dosagem , Estudos Retrospectivos , Medição de Risco/métodos , Fatores Socioeconômicos , Fraturas da Coluna Vertebral/induzido quimicamente , Fraturas da Coluna Vertebral/epidemiologia , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/epidemiologia , Taiwan/epidemiologiaRESUMO
Ulnar shortening is a common procedure for treating ulnar wrist pain of various causes. Many tools and devices had been reported in the literature to facilitate the procedure, but not all are universally available. Freehand technique is still useful in clinical practice. Here we present a pre-drilled hole method to improve the outcomes of the freehand technique. From 2008 to 2012, a total of 51 patients at our institution underwent ulnar shortening with this method, with an -average follow-up period of 24.4 months (range, 12-62 months). The average shortening length was 4.6âmm (range, 3-8.5âmm). All patients had uneventful union at an average of 9.8 weeks (range, 8-14 weeks) after the surgery. All had improved functional results. All patients returned to their previous full level of work and activities. The pre-drilled hole method for ulnar shortening is an easy assist to the freehand technique. Also, the union rate is high, and complications are uncommon.
Assuntos
Artralgia/cirurgia , Osteotomia/métodos , Articulação do Punho/cirurgia , Seguimentos , Humanos , Resultado do Tratamento , UlnaRESUMO
Pulmonary tuberculosis (TB) is a medical and social problem, particularly in developing countries. Early diagnosis and treatment is important. Chest radiography is usually the first diagnostic tool when there is a suspicion of pulmonary TB. A computed tomography (CT) scan provides more accurate information on the extent and distribution of pulmonary TB. We present here a young, immunocompetent male patient with unusual imaging findings for pulmonary TB. We discuss the clinical presentation and management.
Assuntos
Cistos/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Tuberculoma/diagnóstico por imagem , Tuberculose Pulmonar/diagnóstico por imagem , Antituberculosos/uso terapêutico , Terapia Combinada , Cistos/imunologia , Cistos/microbiologia , Cistos/terapia , Quimioterapia Combinada , Humanos , Imunocompetência , Masculino , Mycobacterium tuberculosis/isolamento & purificação , Pneumonectomia , Toracotomia , Resultado do Tratamento , Tuberculoma/imunologia , Tuberculoma/microbiologia , Tuberculoma/terapia , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/microbiologia , Tuberculose Pulmonar/terapia , Adulto JovemRESUMO
Pulmonary carcinosarcoma is a rare malignancy composed of epithelial and mesenchymal elements. In general, these neoplasms occur in older individuals at the age of 60 on average and are more commonly found in males who are heavy smokers. We report a 25-year-old male with a tumour shadow of the right middle lobe that was revealed by chest X-ray during a health checkup and was confirmed by subsequent computed tomography. The patient underwent thoracotomy with right middle lobe lobectomy. Histological examination of the resected specimen showed adenocarcinoma and undifferentiated sarcoma components. The clinical and histopathologic features of this rare tumour are discussed with a review of the literature.
Assuntos
Carcinossarcoma/patologia , Neoplasias Pulmonares/patologia , Adulto , Humanos , MasculinoRESUMO
PURPOSE: To collect up-to-date data in healthy children to create a digital hand atlas (DHA) that can be used to evaluate, on the basis of the Greulich and Pyle atlas method, racial differences in skeletal growth patterns of Asian, African American, white, and Hispanic children in the United States. MATERIALS AND METHODS: This retrospective study was HIPAA compliant and approved by the institutional review board. Informed consent was obtained from all subjects or their guardians. From May 1997 to March 2008, a DHA containing 1390 hand and wrist radiographs obtained in male and female Asian, African American, white, and Hispanic children with normal skeletal development was developed. The age of subjects ranged from 1 day to 18 years. Each image was read by two pediatric radiologists working independently and without knowledge of the subject's chronologic age, and evaluation was based on their experience with the Greulich and Pyle atlas. Statistical analyses were performed with the paired-samples t test and analysis of variance to study racial differences in growth patterns. P Assuntos
Determinação da Idade pelo Esqueleto/estatística & dados numéricos
, Asiático
, Negro ou Afro-Americano
, Desenvolvimento Ósseo/fisiologia
, Mãos/diagnóstico por imagem
, Hispânico ou Latino
, População Branca
, Adolescente
, Determinação da Idade pelo Esqueleto/normas
, Criança
, Pré-Escolar
, Feminino
, Humanos
, Lactente
, Masculino
, Computação Matemática
, Valores de Referência
, Estudos Retrospectivos
, Caracteres Sexuais
, Software
RESUMO
RATIONALE AND OBJECTIVES: To analyze the effect of a computer-aided diagnosis (CAD) system on clinicians' performance in detection of small acute intracranial hemorrhage (AIH) on computed tomography (CT). MATERIALS AND METHODS: The authors have developed a CAD scheme that used both image processing techniques and anatomic knowledge based classification system to improve diagnosis of small AIH on CT. A multiple-reader, multiple-case receiver operating characteristic (ROC) study was performed. Twenty clinicians, including seven emergency physicians, seven radiology residents, and six radiology specialists were recruited as readers of 60 sets of brain CT, including 30 cases that show AIH smaller than 1 cm, and 30 controls. Each reader read the same 60 cases twice, first without, then with the prompts produced by the CAD system. The clinicians ranked their confidence in diagnosing a case of showing AIH, which produced the ROC curves. RESULTS: Significantly improved performance is observed in emergency physicians, average area under the ROC curve (Az) increased from 0.8422 to 0.9294 (P = .0107) when they make the diagnosis without and with the support of CAD. Az for radiology residents increased from 0.9371 to 0.9762 (P = .0088). Az for radiology specialists increased from 0.9742 to 0.9868, but was statistically insignificant (P = .1755). CONCLUSIONS: CAD can improve the clinicians' performance in detecting AIH on CT. In particular, emergency physicians can benefit most from the CAD and improve their performance to a level approaching that of the average radiology residents.
Assuntos
Competência Clínica , Diagnóstico por Computador , Hemorragias Intracranianas/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Doença Aguda , Algoritmos , Área Sob a Curva , Medicina de Emergência , Humanos , Interpretação de Imagem Assistida por Computador , Processamento de Imagem Assistida por Computador/métodos , Internato e Residência , Bases de Conhecimento , Variações Dependentes do Observador , Curva ROC , Radiologia/educação , Sensibilidade e EspecificidadeRESUMO
Cdc15p is an essential protein kinase and functions with a group of late mitotic proteins that includes Lte1p, Tem1p, Cdc14p and Dbf2p/Dbf20p to inactivate Cdc28p-Clb2p at the end of mitosis in budding yeast [1] [2]. Cdc14p is activated and released from the nucleolus at late anaphase/telophase to dephosphorylate important regulators of Cdc28p-Clb2p such as Hct1p/Cdh1p, Sic1p and Swi5p in a CDC15-dependent manner [3] [4] [5] [6] [7]. How Cdc15p itself is regulated is not known. Here, we report that both the phosphorylation and localization of Cdc15p are cell cycle regulated. The extent of phosphorylation of Cdc15p gradually increases during cell-cycle progression until some point during late anaphase/telophase when it is rapidly dephosphorylated. We provide evidence suggesting that Cdc14p is the phosphatase responsible for the dephosphorylation of Cdc15p. Using a Cdc15p fusion protein coupled at its carboxyl terminus to green fluorescent protein (GFP), we found that Cdc15p, like its homologue Cdc7p [8] in fission yeast, localizes to the spindle pole bodies (SPBs) during mitosis. At the end of telophase, a portion of Cdc15p is located at the mother-bud neck, suggesting a possible role for Cdc15p in cytokinesis.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Proteínas Quinases/metabolismo , Proteínas Tirosina Fosfatases , Proteínas de Saccharomyces cerevisiae , Fuso Acromático/metabolismo , Ciclo Celular , Mitose/fisiologia , Fosfoproteínas Fosfatases/metabolismo , Fosforilação , Proteínas Recombinantes de Fusão/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismoRESUMO
The HIS4 gene in Saccharomyces cerevisiae was put under the transcriptional control of RNA polymerase I to determine the in vivo consequences on mRNA processing and gene expression. This gene, referred to as rhis4, was substituted for the normal HIS4 gene on chromosome III. The rhis4 gene transcribes two mRNAs, of which each initiates at the polymerase (pol) I transcription initiation site. One transcript, rhis4s, is similar in size to the wild-type HIS4 mRNA. Its 3' end maps to the HIS4 3' noncoding region, and it is polyadenylated. The second transcript, rhis4l, is bicistronic. It encodes the HIS4 coding region and a second open reading frame, YCL184, that is located downstream of the HIS4 gene and is predicted to be transcribed in the same direction as HIS4 on chromosome III. The 3' end of rhis4l maps to the predicted 3' end of the YCL184 gene and is also polyadenylated. Based on in vivo labeling experiments, the rhis4 gene appears to be more actively transcribed than the wild-type HIS4 gene despite the near equivalence of the steady-state levels of mRNAs produced from each gene. This finding indicated that rhis4 mRNAs are rapidly degraded, presumably due to the lack of a cap structure at the 5' end of the mRNA. Consistent with this interpretation, a mutant form of XRN1, which encodes a 5'-3' exonuclease, was identified as an extragenic suppressor that increases the half-life of rhis4 mRNA, leading to a 10-fold increase in steady-state mRNA levels compared to the wild-type HIS4 mRNA level. This increase is dependent on pol I transcription. Immunoprecipitation by anticap antiserum suggests that the majority of rhis4 mRNA produced is capless. In addition, we quantitated the level of His4 protein in a rhis4 xrn1delta genetic background. This analysis indicates that capless mRNA is translated at less than 10% of the level of translation of capped HIS4 mRNA. Our data indicate that polyadenylation of mRNA in yeast occurs despite HIS4 being transcribed by RNA polymerase I, and the 5' cap confers stability to mRNA and affords the ability of mRNA to be translated efficiently in vivo.
Assuntos
Proteínas Fúngicas/biossíntese , Complexos Multienzimáticos/biossíntese , Biossíntese de Proteínas , RNA Polimerase I/metabolismo , RNA Mensageiro/metabolismo , Proteínas de Saccharomyces cerevisiae , Fatores de Transcrição/biossíntese , Oxirredutases do Álcool , Aminoidrolases , Sequência de Bases , DNA Fúngico/metabolismo , DNA Ribossômico/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Exorribonucleases/genética , Exorribonucleases/metabolismo , Dados de Sequência Molecular , Mutagênese , Pirofosfatases , RNA Polimerase II/metabolismo , Saccharomyces cerevisiae/genética , Transcrição GênicaRESUMO
RATIONALE AND OBJECTIVES: Most health care facilities currently struggle with protecting medical data privacy, misidentification of patients, and long patient waiting times. This article demonstrates a novel system for a clinical environment using wireless tracking and facial biometric technologies to automatically monitor and identify staff and patients to address these problems. MATERIALS AND METHODS: The design of the location tracking and verification system (LTVS) was based on a workflow study which was performed to observe the physical location and movement of patient and staff at the Healthcare Consultation Center II (HCC II) running hospital information systems, radiology information systems, picture archive and communication systems, and a voice recognition system. Based on the results from this workflow study, the LTVS was designed using a wireless real-time location system and a facial biometric system integrated with the radiology information system. The LTVS was tested for its functionality in a laboratory environment, then evaluated at HCC II. RESULTS: Experimental results in the laboratory and clinical environments demonstrated that patient and staff real-time location information and identity verification can be obtained from LTVS. Warning messages can immediately be sent to alert staff when patient's waiting time is over a predefined limit, and unauthorized access to a security area can be audited. Additionally, patient misidentification can be prevented during the course of examinations. CONCLUSIONS: The system enabled health care providers to streamline the patient workflow, protect against erroneous examinations and create a security zone to prevent, and audit unauthorized access to patient health care data required by the Health Insurance Portability and Accountability Act mandate.
Assuntos
Sistemas de Informação Hospitalar , Sistemas de Informação em Radiologia , Segurança Computacional , Custos e Análise de Custo , Sistemas de Informação Hospitalar/economia , Sistemas de Identificação de Pacientes , Sistemas de Informação em Radiologia/economia , Interface para o Reconhecimento da FalaRESUMO
Polyubiquitination marks proteins for degradation by the 26S proteasome and is carried out by a cascade of enzymes that includes ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s). The anaphase-promoting complex or cyclosome (APC/C) comprises a multisubunit ubiquitin ligase that mediates mitotic progression. Here, we provide evidence that the Saccharomyces cerevisiae RING-H2 finger protein Apc11 defines the minimal ubiquitin ligase activity of the APC. We found that the integrity of the Apc11p RING-H2 finger was essential for budding yeast cell viability, Using purified, recombinant proteins we showed that Apc11p interacted directly with the Ubc4 ubiquitin conjugating enzyme (E2). Furthermore, purified Apc11p was capable of mediating E1- and E2-dependent ubiquitination of protein substrates, including Clb2p, in vitro. The ability of Apc11p to act as an E3 was dependent on the integrity of the RING-H2 finger, but did not require the presence of the cullin-like APC subunit Apc2p. We suggest that Apc11p is responsible for recruiting E2s to the APC and for mediating the subsequent transfer of ubiquitin to APC substrates in vivo.
Assuntos
Proteínas Fúngicas/metabolismo , Ligases/metabolismo , Complexos Ubiquitina-Proteína Ligase , Ubiquitinas/metabolismo , Dedos de Zinco , Sequência de Aminoácidos , Ciclossomo-Complexo Promotor de Anáfase , Animais , Subunidade Apc11 do Ciclossomo-Complexo Promotor de Anáfase , Sobrevivência Celular , Proteínas Fúngicas/genética , Humanos , Ligases/genética , Dados de Sequência Molecular , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Enzimas de Conjugação de Ubiquitina , Ubiquitina-Proteína LigasesRESUMO
We have developed an automated method to assess bone age of children using a digital hand atlas. The hand atlas consists of two components. The first component is a database which is comprised of a collection of 1400 digitized left hand radiographs from evenly distributed normally developed children of Caucasian (CA), Asian (AS), African-American (AA) and Hispanic (HI) origin, male (M) and female (F), ranged from 1- to 18-year-old; and relevant patient demographic data along with pediatric radiologists' readings of each radiograph. This data is separate into eight categories: CAM, CAF, AAM, AAF, HIM, HIF, ASM, and ASF. In addition, CAM, AAM, HIM, and ASM are combined as one male category; and CAF, AAF, HIF, and ASF are combined as one female category. The male and female are further combined as the F & M category. The second component is a computer-assisted diagnosis (CAD) module to assess a child bone age based on the collected data. The CAD method is derived from features extracted from seven regions of interest (ROIs): the carpal bone ROI, and six phanlangeal PROIs. The PROIs are six areas including the distal and middle regions of three middle fingers. These features were used to train the 11 category fuzzy classifiers: one for each race and gender, one for the female, one male, and one F & M, to assess the bone age of a child. The digital hand atlas is being integrated with a PACS for validation of clinical use.
Assuntos
Determinação da Idade pelo Esqueleto/métodos , Ossos da Mão/diagnóstico por imagem , Sistemas de Informação em Radiologia , Adolescente , Criança , Pré-Escolar , Feminino , Transtornos do Crescimento/diagnóstico , Ossos da Mão/metabolismo , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Lactente , Masculino , Estados UnidosRESUMO
Imaging-matching is an important research area in imaging informatics. We have developed and evaluated a novel diagnostic support tool (DST) based on medical image matching using MR brain images. The approach consists of two steps, database generation and image matching. The database contains pre-diagnosed MR brain images. As the images are added to the database, they are registered to the 3D Talairach coordinate system. In addition, regions of interests (ROI) are generated, and image-processing techniques are used to extract relevant image parameters related to the brain and diseases from the ROIs and from the entire MR image. The second step is to retrieve relevant information from the database by performing image matching. In this step, the physician first submits a query image. The DST computes the similarity between the query image and each of the images in the database, and then presents the most similar images to the user. Since the database contains pre-diagnosed images, the retrieved cases tend to contain relevant diagnostic information. To evaluate the usefulness of the DST in a clinical setting, pediatric brain diseases were used. The database contains 2500 pediatric patients between ages 0 and 18 with brain Magnetic Resonance (MR) images of known brain lesions. A testbed was established at the Children's Hospital Los Angeles (CHLA) for acquiring MR images from the PACS server of patients with known lesions. These images were matched against those in the DST pediatric brain MR database. An expert pediatric neuroradiologist evaluated the matched results. We found that in most cases, the image-matching method was able to quickly retrieve images with relevant diagnostic content. The evaluation method and results are given.
Assuntos
Encefalopatias/diagnóstico , Criança , Humanos , Imageamento por Ressonância Magnética , Estados UnidosRESUMO
UNLABELLED: We compared the short-term (3 months) and long-term (2 years) outcomes and complications of percutaneous release of 187 trigger digits of 154 patients treated between 2009 and 2012, all treated by a single surgeon. The 154 patients included 48 patients with diabetes mellitus and 106 non-diabetic patients. The only short-term complication was pain, occurring in three digits (5%) in the diabetic patients and six digits (5%) in the non-diabetic patients. The long-term complications were pain in 15 digits (25%) in the diabetic patients and 18 digits (14%) in the non-diabetic patients. This was not significant (p = 0.058). Recurrent triggering occurred in nine digits (15%) in the diabetic patients, which was significantly greater than the six digits (5%) in the non-diabetic patients (p = 0.013). The non-diabetic patients were significantly more satisfied. LEVEL OF EVIDENCE: level III.
Assuntos
Complicações do Diabetes , Dedo em Gatilho/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Dor Pós-Operatória/etiologia , Satisfação do Paciente/estatística & dados numéricos , Recidiva , Dedo em Gatilho/complicaçõesRESUMO
We compared the computed tomographic (CT) scans of 46 patients with dementia with those of 46 normal subjects matched for age and sex. We measured the areas subtended by the third ventricle, frontal horns, bodies of the lateral ventricles, and interhemispheric fissure as depicted in CT sections, then determined the ratio between each of those areas and the entire brain at each level. Patients with dementia had significantly larger ratios on all measures. A multivariate classification procedure showed that a composite formula of two measures, the bodies of the lateral ventricles and the interhemispheric fissure, predicted clinical status in 84% of the cases. Findings indicated that some CT measurements reflected cerebral changes associated with dementia. If appreciated in a suitable probabilistic framework, these data may be clinically useful in supporting or weakening the diagnostic hypothesis of dementia in the many cases in which diagnosis is unclear.
Assuntos
Demência/diagnóstico , Tomografia Computadorizada por Raios X , Idoso , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
OBJECTIVES AND RATIONALE: In a picture archiving and communication system (PACS), images are acquired from multiple modalities and displayed on an electronic workstation. Each modality has different image characteristics. This variability must be addressed before the image is displayed. METHODS: The authors developed methods to automatically process magnetic resonance (MR), computed tomographic (CT), and computed radiography (CR) images before display and subjectively evaluated their effectiveness. RESULTS: Unwanted background successfully was automatically removed from 89.5% of 615 CR images. Of 803 chest, abdomen, and hand images 93% were automatically rotated to the correct orientation. CONCLUSIONS: Automated preprocessing of PACS images can be performed successfully, improving speed and convenience for the radiologist interpreting images at an electronic workstation.
Assuntos
Processamento de Imagem Assistida por Computador , Sistemas de Informação em Radiologia , Imageamento por Ressonância Magnética , Intensificação de Imagem Radiográfica/métodos , Tomografia Computadorizada por Raios XRESUMO
RATIONALE AND OBJECTIVES: To synthesize magnetic resonance images (MRI) in real-time using a minimal data set obtained with routine clinical protocols and stored in a picture archiving and communication system (PACS) database. METHODS: Analytic solutions for T1 and T2 were obtained from a double and a single spin-echo set, with routine parameters. Analytic solutions from radio frequency-spoiled gradient-echo images, with TRs as low as 33 mseconds, also were used to synthesize gradient-echo images. RESULTS: Phantom studies showed that the errors in the synthesized images were significantly smaller than the errors in the T1- and T2-calculated images and similar to the source images. The gradient-echo images resulted in significant scan time savings. CONCLUSION: MRI synthesis from analytic solutions of T1, T2, and rho saves computational time and yields accurate values for the intrinsic parameters while allowing the use of routine clinical protocols. The availability of clinical images in the PACS database and the ability to synthesize images in real-time has allowed the development of a practical interactive teaching module.
Assuntos
Imageamento por Ressonância Magnética/métodos , Encéfalo/anatomia & histologia , Humanos , Modelos EstruturaisRESUMO
The experience with CR systems gained at the three institutions described in this report demonstrates numerous advantages over the conventional screen-film system. These include: (1) a reduction in the radiation exposure delivered to the patient (25% to 50%); (2) a decrease in the number of repeat examinations needed, especially in portable units where technical difficulties are common with screen-film examinations; this is attributable to the linear, wider dynamic range of CR systems compared with screen-film combinations; (3) the capability to archive electronically all images by means of a digital optical storage system; (4) automatic electronic setting of the laser scanner for the latitude and sensitivity on each image; (5) the digital images are available for transmission to all image display workstations on a local or wide-area network; and (6) the ability to adjust interactively the display parameters to best depict images and pathology as well as salvage technically suboptimal examinations. Several disadvantages of CR systems compared with conventional screen-film examinations have also been identified.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Ecrans Intensificadores para Raios X , Humanos , Medições LuminescentesRESUMO
RATIONALE AND OBJECTIVES: Digital image compression reduces the storage requirements and network traffic on picture archiving and communications systems. Full-frame bit-allocation (FFBA) is an irreversible image-compression method based on the discrete cosine transform that provides for high compression ratios with a high degree of image fidelity. METHODS: One hundred twenty-two posteroanterior chest radiographs were obtained on patients in an ambulatory patient setting, including 30 cases of interstitial lung disease, 45 images containing combinations of lung nodules (N = 37) or mediastinal masses (N = 39), and 47 normal images containing none of the pathology for which we were testing. The images were digitized (nominal 2 K x 2 K x 12-bit resolution), printed on a 35 x 35-cm hard copy format, and compressed at an approximate compression ratio of 20:1. Observer performance tests were conducted with five radiologists using receiver operating characteristics analysis on digitized uncompressed and compressed hard copy images. RESULTS: There were no significant differences between the two display conditions for the detectability of any of the thoracic abnormalities. CONCLUSIONS: Our preliminary results suggest that irreversible image compression at ratios of 20:1 may be acceptable for use in digital thoracic imaging.
Assuntos
Doenças do Mediastino/diagnóstico por imagem , Fibrose Pulmonar/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Nódulo Pulmonar Solitário/diagnóstico por imagem , Algoritmos , Humanos , Doenças do Mediastino/epidemiologia , Fibrose Pulmonar/epidemiologia , Curva ROC , Radiografia Torácica/métodos , Sistemas de Informação em Radiologia , Nódulo Pulmonar Solitário/epidemiologiaRESUMO
This paper focuses on analysis and development of a single-exposure dual-energy digital radiographic method using computed radiography (Fuji FCR-101 storage phosphor system). A detector sandwich consisting of storage phosphor imaging plates and an interdetector filter is used. The goal of this process is to provide a simple dual-energy method using typical plane-projection radiographic equipment and techniques. This approach exploits the transparency of the storage phosphor plates, using radiographic information that would be otherwise lost, to provide energy selective information essentially as a by-product of the radiographic examination. In order to effectively make use of the large dynamic range of the storage phosphor imaging plates (10,000:1), a computed radiography image reading mode of fixed analog-to-digital converter gain and variable photomultiplier sensitivity provides image data which can be related to relative incident exposure for export to the decomposition algorithm. Scatter rejection requirements necessitated crossed 12:1 grids for a field size of 36 x 36 cm. Optimal technique parameters obtained from computer simulation through minimization of the aluminum and Plexiglas equivalent image uncertainty under conditions of constant absorbed does resulted as: 100 kVp using a 0.15-mm-thick tin (Sn) interdetector filter for the lung field. This yields a surface exposure of 23 mR and a surface absorbed dose of 0.26 mGy for a 23-cm-thick chest. Clinical application in evaluation of the solitary pulmonary nodule is discussed, along with an image set demonstrating this application.